In conventional packet forwarding apparatuses, the input rate and the output rate are monitored. In the future, it is predicted that there will be a demand for increased data capacity and for detailed rate monitoring. Accordingly, there is a demand for an architecture which meets such a demand.
The data collection capacity of an interface unit for a device which performs data forwarding etc., has been increasing year by year.
Until a few years ago, Fast Ether (FE, bit rate: 100 Mbps) and Giga Bit Ether (GbE, bit rate: 1 Gbps) were the mainstream. However, in recent years, network data capacity has been increasing. Furthermore, 10 GbE (10 Giga Bit Ether, bit rate: 10 Gbps) interfaces have increased, typical examples of which include backbone networks.
An interface unit provides a Quality of Service (QoS) function. This function provides policing (rate monitoring) operations for forwarding data or discarding data, etc., in increments of users.
Until a few years ago, interface units that bundled FE or GbE were the mainstream, and the data collection rate of the unit was around 10 GbE. In recent years, increased data capacity has required a unit that bundles 10 GbE data, and has further required a unit that bundles 20 GbE. At the same time, there is a demand for detailed data monitoring of the data thus collected.
Ordinary policing methods provide such rate monitoring by performing operation processing and memory access in increments of packets as disclosed in Japanese Laid-open Patent Publication No. 2001-308881. However, there are limits to such operation processing speed and memory access, leading to a problem in that such a method does not meet the demand for increased data capacity and detailed rate monitoring.